A medical suturing needle used for suturing biological tissue is typically formed so as to be curved from a needle tip through a trunk portion to a proximal end. The curved shape has substantially the same curvature radius over the entire length and is formed in a shape (at an angle) of a ½ circle) (180°), a ⅜ circle)(135°), or a ¼ circle)(90°).
As a bending method which curves a shaft rod shaped material when the curved medical suturing needle is manufactured, there is a technique described in Patent Document 1. In this technique, a material is inserted into between a cylindrical bending roll and a belt pressed into contact with and wound around the outer circumference of the bending roll and having flexibility, the material is wound by the bending roll and the belt so as to be bent along the outer circumferential surface of a bending die, and the bent material is rewound and is discharged. Thus, the shaft rod shaped material is curved.
A bicurve needle which is a medical suturing needle mainly used for an eye operation is curvedly formed so that a needle tip portion and a trunk portion have different curvature radii. As one bending method of such medical suturing needle, a technique described in Patent Document 2 has been proposed.
In the technique described in Patent Document 2, a straight needle material molded in a predetermined sectional shape is bent from one end side over a predetermined range at the largest curvature radius configuring a curved shape, the bent material is bent from the end of the material over a predetermined range at a curvature radius smaller than the above curvature radius, and the material is bent from the end of the material over a predetermined range so that the curvature radius is sequentially reduced. In this technique, plural bending rolls having different curvature radii corresponding to the curved shape of the medical suturing needle are prepared, and the material is sequentially bent by the bending rolls. Thus, the material can be reasonably bent.    Patent Document 1: U.S. Pat. No. 1,295,902    Patent Document 2: U.S. Pat. No. 3,078,339